Stage 1[edit]
Welcome to the game. Once your Fighters have come flying up into view from the bottom of the screen and the background has faded in, four Zako and four Goei will come flying down into view from the top of it, and circle around before taking their places in the formation; once you have fired a shot at as many of them as you can to kill them, four Boss Galagas and four more Goei will come flying into view from the left side of the screen, and circle around before taking their places in the formation. Once you have fired a single shot at as many of the Goei (and two shots at as many of the Boss Galagas) as you can to kill them, eight more Goei will fly into view from the right side of the screen and circle around before taking their places in the formation - and once you have fired a shot at as many of them as you can to kill them, two more groups of eight more Zako will come flying down into view from the top of the screen, then circle around before taking their places in the formation. Once you have fired a shot at as many of these as you can to kill them, any remaining enemies in the formation will start to attack your Fighters (any remaining Boss Galagas will also try to capture them with their tractor beams); as in the original Galaga, if your Fighter gets captured by a Boss Galaga, it will spin around in a clockwise direction as it's beamed up (but it can still fire shots at the enemies, so if you manage to kill the offending Boss Galaga before your Fighter reaches it, it will be freed). However, if you do not manage to kill the offending Boss Galaga in time, your captured Fighter will turn gray and the Boss Galaga will fly back up to the top of the formation - and if you have more than one life remaining, the next Fighter will fly up into view from the bottom of the screen (but if you do not, the game will end). Once either player has killed the offending Boss Galaga while he is attacking, the now-retrieved Fighter shall return to its original colour, and drop back down to the bottom of the screen to join up with the one that retrieved it, which creates a Blue Dual Fighter; however, the Boss Galagas, Boss Choucho, and Boss Tentoumushi on later stages shall still be able to steal this with their tractor beams. Once you fire a single shot at each of the remaining Zako and Goei (and two shots at each of the remaining Boss Galagas) to kill them, the text "STAGE CLEAR!!" will appear on the screen, as your Fighters fly up off the top of it - and in one-player mode, the player's number of hits (in this case, 40/40, as all the enemies on this stage must be killed) and shoot down ratio (in this case, 100%) will be displayed in the centre of the screen, but in two-player mode, both players' numbers of hits will be displayed on the left and right sides of it, with the texts of "LOSE" (for the lower one) and "WIN!" (for the higher one) below them (however, if both players should ever score the same number of hits on any stage which has an even number of enemies, the word "DRAW" will be displayed in the centre of the screen below them).
Stage 2[edit]
Once your Fighters have come flying up into view from the bottom of the screen, and the background has faded back in, the text "ASTEROID ZONE" will appear on the screen; a wormhole shall then open up at the bottom of the screen as a Yuubaku Mushi and a Zako emerge from it, and fly upwards while firing a hail of bullets down at you before taking their places in the formation. Once you've fired a shot at each of them to kill them, another wormhole will open up at the top of the screen as sixteen more Zako, sixteen Goei and eight Boss Galagas emerge from it and fly outwards in all eight directions while firing another hail of bullets down at you - and once you have fired a single shot at as many of the Zako and Goei, and two shots at as many of the Boss Galagas as you can to kill them, a maximum of eight of the Zako, twelve of the Goei and four of the Boss Galagas will take their places in the formation, and begin to attack your Fighters. Once you've fired a single shot at each of the remaining Zako and Goei (and two shots at each of the remaining Boss Galagas) in the formation to kill them, the text of "STAGE CLEAR!!" shall appear on the screen, as your Fighters fly up off the top of it to the third stage.
Stage 3[edit]
Once your Fighters have come flying up into view from the bottom of the screen and that background has faded back in, five wormholes will open up at the top of the screen as a Boss Galaga, five Goei, two Yuubaku Mushi, and ten Zako emerge from them, while firing a hail of bullets down at you; once you have fired a single shot at as many of the Zako, Goei, and Yuubaku Mushi as you can to kill them (and two shots at the Boss Galaga, to kill him), a maximum of the Boss Galaga, all the Goei, one of the Yuubaku Mushi and five of the Zako will take their places in the formation. Five more wormholes will then open at the top of the screen as another Boss Galaga, five more Goei, two more Yuubaku Mushi, and ten more Zako emerge from them while firing another hail of bullets down at you - and once you've fired a single shot at as many of the Zako, Goei and Yuubaku Mushi as you can to kill them (and two shots at the Boss Galaga to kill him), a maximum of the Boss Galaga, all five of the Goei, one of the Yuubaku Mushi, and five of the Zako will take their places in the formation. Two more wormholes shall now open up at the top of the screen as two more Boss Galagas, four more Goei and six more Zako emerge from them while firing a third hail of bullets down at you; once you have fired a single shot at as many of the Zako and Goei as you can to kill them, a maximum of the two Boss Galagas, two of the Goei, and four of the Zako will take their places in the formation. All remaining foes in the formation shall now start to attack your Fighters - and once you fire a single shot at each of the remaining Zako, Goei and Yuubaku Mushi and two shots at each of the remaining Boss Galagas to kill them the text "STAGE CLEAR!!" shall appear on the screen as your Fighters fly up off the top of it.
Stage 4[edit]
Once your Fighters have come flying up into view from the bottom of the screen (and that background has faded back in), four Boss Galagas, eighteen Zako and ten Goei will come flying into view from the left and right sides of the screen and circle around while firing a hail of bullets down at you before taking their places in the formation; once you have fired a single shot at each of the Zako and Goei (and two shots at each of the Boss Galagas) in this formation to kill them, two wormholes will open up at the top of the screen as two Yuubaku Mushi, four Batta and four Ogawamushi emerge from them while firing another hail of bullets down at you. Once you have fired a shot at each of these to kill them, the text "STAGE CLEAR!!" shall appear on the screen as your Fighters fly up off the top of it to the fifth stage - which is the first of the five "Challenging Stages" where the enemies do not attack you.
Stage 5 (Challenging Stage)[edit]
Once your Fighters have come flying up into view from the bottom of the screen and that background has faded back in again, the text "CHALLENGING STAGE" will fly into view from its right side and off its left one; the background will now scroll upwards as ten Ogawamushi fly into view from the left side of the screen and circle around. Once you have fired a shot at each of them to kill them, the background shall scroll to the left as ten more Ogawamushi come flying into view from the right side of the screen and circle around - and once you have fired a shot at all of them to kill them, the background shall scroll upwards again, as six Zako fly into view from the left side of the screen and circle around. Once you have fired a shot at each of them to kill them, the background shall change as six Goei fly into view from the right side of the screen and circle around; once you have fired a shot at all of these to kill them, two Boss Tentoumushi, two final Goei, two final Zako, and two Batta will fly down into view from the top of the screen as the background changes a maximum of five more times in succession. Once you've fired two shots at both of the Boss Tentoumushi (and a single shot at both of the Goei, Zako, and Batta to kill them), your Fighters shall fly up off the top of the screen - and the text "RESULTS" will then fly onto the screen from its top-right corner.
In one-player mode the player's number of hits and bonus of 100 points per hit will be tabulated in the centre of the screen, and if he or she managed to kill all forty enemies, the text of "PERFECT! SPECIAL BONUS 10000 PTS" will appear below it; however, in two-player mode, both players' numbers of hits and bonuses of 100 points per hit will be tabulated on the left and right sides of the screen and the text "PERFECT! SPECIAL BONUS 10000 PTS" shall appear under that of the higher one (even if that player did not actually kill all forty enemies). Your Fighters shall now proceed to the Nebula Zone.
Note: If you do not move your Fighter or fire any shots at the enemies during this stage, the text of "LUCKY! AUDIENCE BONUS 7650 PTS" will appear below your number of hits (which will obviously be 0) and bonus (which will obviously be "NONE") at the end of it; 7650 is Namco's goroawase number.